We have developed a Monte Carlo simulator of the electromigration process in polycrystalline metal stripes. Stripes with different average grain size can be generated with Voronoi tesselation, and mapped onto a network of resistors. The proposed model includes the major role played by grain boundaries and by the current density redistribution within the stripe following void formation. Simulations of stripes with different grain sizes and different widths are shown, and a few expressions for the failure probability are compared on the basis of their capability of reproducing the experimental results. In addition, electromigration noise has been computed, recovering the characteristic 1/f γ (γ ≈ 2) behaviour. The substantial qualitative agreement between our calculations and the experimental results is a convincing test of the capability of the model proposed to include the relevant physics.